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Not applicable.
The present invention generally relates to a locking device for securing a rotatable handle. More particularly, the present invention relates to a pipe valve lockout assembly for securing a ball valve handle in a closed or open position relative to the pipe containing the valve.
Pipes that convey liquid or gas generally include valve systems that allow an operator to block or open the passageway through the pipe. A ball valve is situated in the passageway of the pipe and may be adjusted to block the passageway by rotating a valve handle to a position perpendicular to the pipe. Alternatively, the ball valve may be adjusted to open the passageway by rotating the valve handle to a position parallel and alongside the pipe. Often the valve handle needs to be secured in the open or closed position by a valve lockout assembly to ensure the safety of those working on the pipe or on equipment connected to the pipe. For example, the valve lockout assembly prevents accidental opening of the pipe while maintenance is being performed on the pipe.
A valve lockout assembly is described in U.S. Pat. No. 5,003,797 issued to Wirth that includes a housing and securing leg. The housing includes a chamber having an entrance for receiving a valve handle in the closed position so that the valve handle is positioned within the chamber and at an angle to a side wall of the chamber. The housing is then rotated so that the valve handle is flush with the side wall allowing a securing leg of the housing to engages engage the pipe. A padlock shackle is then positioned through a pair of the aligned apertures in the housing to secure the valve handle in the closed position.
However, such a lockout assembly may not be used to secure a valve handle in the open position where the valve handle is parallel to the pipe. In addition, the assembly is susceptible to being loosened because the tension holding the assembly about the valve handle is generated mainly from the resistance of the bearing surface against one side of the pipe wall. The bearing surface engages only a small surface area of the pipe wall, therefore, the securing leg may become disengaged from the pipe wall and leave the valve handle unsecured.
It is therefore an object of the present invention to provide an improved valve lockout device.
It is another object of the present invention to provide for a valve lockout assembly that is compatible with a valve handle in the open position or in the closed position.
These and other objects of the invention are achieved in a valve lock for locking a pipe valve in either its open or its closed position. A typical pipe valve has a longitudinally extending handle which is rotatable relative to the axis of the pipe containing the valve. The valve occupies a closed position when the handle is at a position orthogonal to the axis of the pipe, and occupies an open position when the handle is at a position parallel to the axis of the pipe. The valve lock includes a pair of mateable housings having contact points for seating against the pipe and a retention chamber shaped for receiving the handle and preventing its movement, The housings have a lock structure which receives the shackle of a padlock for securing the two housings in their mated position about the pipe to restrain movement of the valve handle.